Everything below concerns Heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-26. Numbers and descriptions here follow the published literature rather than marketing material.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
| Property | Value | Notes |
|---|---|---|
| Principal proposed target | GABA-A receptor complex | Hypothesis derived mainly from animal pharmacology |
| Common behavioral assay | Elevated plus maze | Rodent test for anxiety-like behavior |
| Reported molecular marker | Hippocampal BDNF expression | Measured by immunoassay or mRNA quantification |
| Typical dosing route | Intranasal | Chosen to reduce first-pass metabolism |
| Reported plasma half-life | Minutes | Based on limited peptide stability data |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
On April 9, 2026, FIFA announced 52 referees, 88 assistant referees, and 30 video assistant referees for the tournament. The 2026 World Cup featured six female match officials, equalling the record for the highest number of female officials appointed to a men's World Cup. Tori Penso, Brooke Mayo, and Kathryn Nesbitt became the second all-female on-field refereeing trio at a men's World Cup, officiating the Group A match between Czech Republic and South Africa at Atlanta Stadium. On June 9, Somali referee Omar Artan was refused entry into the United States despite holding valid travel documents, and FIFA later removed him from the list of referees. FIFA stated that Artan would receive his full World Cup salary despite not being able to officiate in the tournament.
2,4,6-Triisopropylbenzenesulfonyl azide (trisyl azide) is an organic chemical used as a reagent to supply azide for electrophilic amination reactions, such as for the asymmetric synthesis of unnatural amino acids. Introduction of an azide on the α carbon of carboxylic acid derivatives using trisyl azide is an efficient alternative to electrophilic halogenation followed by nucleophilic substitution using anionic azide. Using an oxazolidinone as chiral auxiliary typically gives good induction of the stereochemistry at the α position. Subsequent reduction converts the α-azide to an α-amine.
Germany, the birthplace of decaffeinated coffee, is home to several decaffeination plants, including the world's largest, Coffein Compagnie. Over half of the decaf coffee sold in the US first travels from the tropics to Germany for caffeine removal before making its way to American consumers. Coffee manufacturers recover the caffeine and resell it for use in soft drinks and over-the-counter caffeine tablets. The efficiency and selectivity of caffeine removal depend on the decaffeination method used. Water-based processes and supercritical carbon dioxide extraction are generally more selective, as they remove caffeine while preserving a larger proportion of volatile flavor compounds compared to some organic solvent methods. Extraction of caffeine from coffee, to produce caffeine and decaffeinated coffee, can be performed using various solvents. Following are main methods:
The US Food and Drug Administration (FDA) requires all antidepressants, including venlafaxine, to carry a black box warning with a generic warning about a possible suicide risk. A 2014 meta-analysis of 21 clinical trials of venlafaxine for the treatment of depression in adults found that compared to placebo, venlafaxine reduced the risk of suicidal thoughts and behavior. A study conducted in Finland followed more than 15,000 patients for 3.4 years. Venlafaxine increased suicide risk by 60% (statistically significant), as compared to no treatment. At the same time, fluoxetine (Prozac) halved the suicide risk. In a study sponsored by Wyeth, which produces and markets venlafaxine, the data on more than 200,000 cases were obtained from the UK general practice research database. At baseline, patients prescribed venlafaxine had a greater number of risk factors for suicide (such as prior suicide attempts) than patients treated with other anti-depressants. The patients taking venlafaxine had a significantly higher risk of suicide than the ones on fluoxetine or citalopram (Celexa). After adjusting for known risk factors, venlafaxine was associated with an increased risk of suicide relative to fluoxetine and dothiepin which was not statistically significant. A statistically significant greater risk for attempted suicide remained after adjustment, but the authors concluded that it could be due to residual confounding.
Sources: en.wikipedia.org
== Further reading == He, Ran; Cao, Jie; Tan, Tieniu (2025). "Generative Artificial Intelligence: A Historical Perspective". National Science Review. 12 (5) nwaf050. doi:10.1093/nsr/nwaf050. PMC 11970245. PMID 40191253. James Gleick, "The Parrot in the Machine" (review of Emily M. Bender and Alex Hanna, The AI Con: How to Fight Big Tech's Hype and Create the Future We Want, Harper, 274 pp.; and James Boyle, The Line: AI and the Future of Personhood, MIT Press, 326 pp.), The New York Review of Books, vol. LXXII, no. 12 (24 July 2025), pp. 43–46. "[C]hatbox 'writing' has a bland, regurgitated quality. Textures are flattened, sharp edges are sanded. No chatbox could ever have said that April is the cruelest month or that fog comes on little cat feet (though they might now, because one of their chief skills is plagiarism). And when synthetically extruded text turns out wrong, it can be comically wrong. When a movie fan asked Google whether a certain actor was in Heat, he received this 'AI Overview': 'No, Angelina Jolie is not in heat.'" (p. 44.)
The large intestine forms an arch starting at the cecum and ending at the rectum and anal canal. It also includes the appendix, which is attached to the cecum. Its length is about 1.5 m, and the area of the mucosa in an adult human is about 2 m2 (22 sq ft). The longest part of the large intestine is the colon whose main function is to absorb water and salts. The large intestine begins at the cecum, where the appendix is located. This is also the start of the colon as the ascending colon in the back wall of the abdomen. At the right colic flexure (hepatic flexure) (the flexed portion of the ascending and transverse colon) it runs across the abdomen in the transverse colon, passing below the diaphragm. At the left colic flexure (splenic flexure) the flexed portion of the transverse and descending colon, it descends down the left side of the abdomen. It reaches the sigmoid colon which is a loop of the colon closest to the rectum and continues to the rectum and anal canal.
== Isomers == Several isomers of Fumonisin B4 have been detected. A larger group is the partially hydrolysed form, denoted as PHFB4, which has been detected using HPLC-ITMS. Another significant isomer is the 3-epi-FB4, which has been identified using NMR, it has also been shown that this isomer occur 10-40% of the regular FB4 sample in nature.
Sources: en.wikipedia.org
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.
Behavioral endpoints include time spent in open arms of the elevated plus maze and avoidance latencies. Biochemical endpoints include BDNF concentration, cytokine levels, and monoamine metabolite ratios in brain tissue.
Most published studies are small, originate from a limited number of laboratories, and lack independent replication. Dose-response relationships, measured brain exposure, and long-term outcomes are not well characterized.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.